As said before in this forum: it depends on the amp you have. Mine is a Jolida Fusion 3502c, a great piece of iron that can go up to KT150s... good sounding, heavy hitting but kind of lifeless against Genalex KT88s, much more organic, musical, deep bass if a little bit loose for moments. My absolute reference are the Shuguang WEKT88 plus , red base, a limited edition of Western Electric classic tubes, (which by the way never made a KT88) so this one is a big bottle that looks like an old GE 6550. I don't care if chinese or not, those are by far the BEST sounding KT88 tubes I have heard, with the deepest, tightest, fastest bass ever, along with extension, punch and musicality. Maybe expensive, but absolute reference level. I got a quartet in 2019 at a fair price, now it looks like there are very few if any for sale. My advice: get them if you can ¡¡